identifier: traitmech:000519 label: Brc76 system definition: A phage defense system in which an organism possesses a gcu76/Brc76 bacteriophage-resistance integron cassette that supports growth during bacteriophage challenge. definition_source: DOI:10.1126/science.ads0915 trait_category: GENOMICS term_kind: CLASS mapping_status: PROPOSED parent_traits: - traitmech:000209 synonyms: - synonym_text: gcu76 synonym_type: RELATED_SYNONYM source: https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/List_system_article.md - synonym_text: brc76 synonym_type: RELATED_SYNONYM source: DOI:10.1126/science.ads0915 evidence: - reference: DOI:10.1126/science.ads0915 snippet: brc76 L 79.5 92.4 89.1 83.1 notes: Manual transcription of the Supplementary Fig. S2 Brc76 low-MOI E. coli IJ1862 heatmap row; the visible cells show reduced inhibition, including 79.5% for MS2, 92.4% for F1, 89.1% for phi80, and 83.1% for F13. - reference: DOI:10.1126/science.ads0915 snippet: brc76 H 96.6 notes: Manual transcription of the Supplementary Fig. S2 Brc76 high-MOI E. coli IJ1862 heatmap row; the visible MS2 cell shows 96.6% inhibition. - reference: DOI:10.1126/science.ads0915 snippet: defense profiles of identified Bacteriophage Resistance integron Cassettes (BRiCs) against a panel of different phages notes: Kieffer et al. classify positive integron cassettes as BRiCs and compare their defense profiles across a phage panel. - reference: DOI:10.1126/science.ads0915 snippet: 'brc113 brc217 brc76 brcWGS21 brc22 brc23' notes: Kieffer et al. include brc76 among identified BRiCs with predicted attC secondary structures. - reference: DOI:10.1126/science.ads0915 snippet: 'C933 pMBA brc76 E. coli IJ1862' notes: Kieffer et al.'s supplementary construct table lists pMBA brc76 in E. coli IJ1862 for high/low-MOI phage-panel testing. - reference: DOI:10.1126/science.ads0915 snippet: 'C939 pMBA brc76 K. pneumoniae KP5' notes: Kieffer et al.'s supplementary construct table lists the pMBA brc76 plasmid introduced into Klebsiella pneumoniae KP5. - reference: https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/List_system_article.md snippet: '| gcu76 | 10\.1126/science\.ads0915 | Mobile integrons encode phage defense systems | ' notes: The pinned DefenseFinder article registry maps the gcu76 source key to the Kieffer et al. mobile-integron BRiC paper. causal_graphs: - graph_id: brc76_integron_cassette_confers_phage_resistance title: Brc76 BRiCs confer phage resistance description: Conservative system-level sketch linking a gcu76/Brc76 bacteriophage-resistance integron cassette to phage resistance and Brc76 system possession. scope_status: NONMECHANISTIC scope_notes: The graph captures Brc76 at the integron-cassette and phage-resistance-output level without asserting the native host range, exact sensitive-phage breadth outside the reported panels, direct molecular substrate, or a DefenseFinder HMM/rules profile absent from the pinned snapshot. nodes: - node_id: brc76_integron_cassette label: Brc76 integron cassette node_type: GENETIC_ELEMENT description: A mobile integron gene cassette named by the gcu76 source key and curated as Brc76. - node_id: brc76_phage_resistance label: Brc76 phage resistance node_type: BIOLOGICAL_PROCESS description: Reduced phage inhibition in cells carrying the gcu76/Brc76 integron cassette. - node_id: brc76_system_trait label: Brc76 system node_type: TRAIT grounding: traitmech:000519 description: Possession of a genome-encoded Brc76 phage-defense system. - node_id: phage_defense_system label: phage defense system node_type: TRAIT grounding: traitmech:000209 description: Possession of one or more genome-encoded immune systems that inhibit bacteriophage infection. edges: - subject: brc76_integron_cassette predicate: contributes to predicate_id: RO:0002326 object: brc76_phage_resistance description: The gcu76/Brc76 integron cassette contributes to phage resistance during phage-panel assays. evidence: - reference: DOI:10.1126/science.ads0915 snippet: brc76 L 79.5 92.4 89.1 83.1 notes: Manual transcription of the Supplementary Fig. S2 Brc76 low-MOI E. coli IJ1862 heatmap row; the visible cells show reduced inhibition, including 79.5% for MS2, 92.4% for F1, 89.1% for phi80, and 83.1% for F13. - reference: DOI:10.1126/science.ads0915 snippet: brc76 H 96.6 notes: Manual transcription of the Supplementary Fig. S2 Brc76 high-MOI E. coli IJ1862 heatmap row; the visible MS2 cell shows 96.6% inhibition. - subject: brc76_phage_resistance predicate: confers predicate_id: METPO:2007700 object: brc76_system_trait description: Brc76-linked phage resistance realizes the Brc76 system possession trait. evidence: - reference: DOI:10.1126/science.ads0915 snippet: brc76 L 79.5 92.4 89.1 83.1 notes: Manual transcription of the Supplementary Fig. S2 Brc76 low-MOI E. coli IJ1862 heatmap row; the visible cells show reduced inhibition, including 79.5% for MS2, 92.4% for F1, 89.1% for phi80, and 83.1% for F13. - reference: DOI:10.1126/science.ads0915 snippet: brc76 H 96.6 notes: Manual transcription of the Supplementary Fig. S2 Brc76 high-MOI E. coli IJ1862 heatmap row; the visible MS2 cell shows 96.6% inhibition. - reference: DOI:10.1126/science.ads0915 snippet: defense profiles of identified Bacteriophage Resistance integron Cassettes (BRiCs) against a panel of different phages notes: Kieffer et al. classify positive integron cassettes as BRiCs and compare their defense profiles across a phage panel. - subject: brc76_system_trait predicate: is a predicate_id: rdfs:subClassOf object: phage_defense_system description: Brc76 system possession is a phage-defense-system trait. evidence: - reference: DOI:10.1126/science.ads0915 snippet: defense profiles of identified Bacteriophage Resistance integron Cassettes (BRiCs) against a panel of different phages notes: Kieffer et al. classify positive integron cassettes as BRiCs and compare their defense profiles across a phage panel. - reference: DOI:10.1126/science.ads0915 snippet: 'brc113 brc217 brc76 brcWGS21 brc22 brc23' notes: Kieffer et al. include brc76 among identified BRiCs with predicted attC secondary structures. - reference: https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/List_system_article.md snippet: '| gcu76 | 10\.1126/science\.ads0915 | Mobile integrons encode phage defense systems | ' notes: The pinned DefenseFinder article registry maps the gcu76 source key to the Kieffer et al. mobile-integron BRiC paper. discussions: - discussion_id: brc76-defensefinder-model-gap prompt: Resolve Brc76 native host breadth, exact sensitive-phage breadth, molecular output, and DefenseFinder HMM/rules coverage before minting narrower Brc76 mechanism children. kind: KNOWLEDGE_GAP status: OPEN rationale: Kieffer et al. identify brc76 as a bacteriophage-resistance integron cassette, and the pinned DefenseFinder article registry maps the gcu76 source key to the same Science article. The pinned HMM inventory and rules table have no exact gcu76 or Brc76 row, so the first-pass record leaves native-host breadth, profile boundaries, exact phage target breadth, and direct molecular output unresolved. evidence: - reference: DOI:10.1126/science.ads0915 snippet: brc76 L 79.5 92.4 89.1 83.1 notes: Manual transcription of the Supplementary Fig. S2 Brc76 low-MOI E. coli IJ1862 heatmap row; the visible cells show reduced inhibition, including 79.5% for MS2, 92.4% for F1, 89.1% for phi80, and 83.1% for F13. - reference: DOI:10.1126/science.ads0915 snippet: brc76 H 96.6 notes: Manual transcription of the Supplementary Fig. S2 Brc76 high-MOI E. coli IJ1862 heatmap row; the visible MS2 cell shows 96.6% inhibition. - reference: DOI:10.1126/science.ads0915 snippet: defense profiles of identified Bacteriophage Resistance integron Cassettes (BRiCs) against a panel of different phages notes: Kieffer et al. classify positive integron cassettes as BRiCs and compare their defense profiles across a phage panel. - reference: DOI:10.1126/science.ads0915 snippet: 'brc113 brc217 brc76 brcWGS21 brc22 brc23' notes: Kieffer et al. include brc76 among identified BRiCs with predicted attC secondary structures. - reference: DOI:10.1126/science.ads0915 snippet: 'C939 pMBA brc76 K. pneumoniae KP5' notes: Kieffer et al. list brc76 in the heterologous Klebsiella pneumoniae KP5 BRiC panel. - reference: https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/List_system_article.md snippet: '| gcu76 | 10\.1126/science\.ads0915 | Mobile integrons encode phage defense systems | ' notes: The pinned DefenseFinder article registry maps the gcu76 source key to the Kieffer et al. mobile-integron BRiC paper. - reference: https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/Liste_hmm_system.md notes: A structured first-pass search of the pinned DefenseFinder HMM inventory found no exact gcu76, brc76, or Brc76 row. - reference: https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/DefenseFinder_rules.tsv notes: A structured first-pass search of the pinned DefenseFinder rules table found no exact gcu76, brc76, or Brc76 system row. attaches_to: - causal_graphs#brc76_integron_cassette_confers_phage_resistance posed_by: codex posed_date: '2026-10-01' curation_history: - timestamp: '2026-10-01T16:17:37Z' curator: codex action: MINTED_TRAITMECH_ID changes: Minted Brc76 system as a DOI- and DefenseFinder-backed GENOMICS TraitRecord under phage defense system after an ignored-and-hidden duplicate review found no exact live TraitMech, METPO, history, or prior proposal record; kept the graph at BRiC integron-cassette level because the pinned DefenseFinder article registry names gcu76 but the pinned HMM inventory and rules table have no exact Brc76 row; the replacement placeholder is reserved in proposals/metpo_traitmech_v396. llm_assisted: true - timestamp: '2026-10-01T16:17:38Z' curator: codex action: REVIEW_CANONICAL_EXAMPLE_EVIDENCE_GAP changes: Reviewed Brc76 system during initial curation and left canonical_examples empty because the sources support heterologous gcu76/Brc76 phage-resistance assays and a DefenseFinder gcu76 article row, but not a direct named native microbial isolate exemplar with experimentally verified endogenous Brc76 activity. No paid research was used. llm_assisted: true